Goverment managing area by pouring in policy Regional Planology Plan it's called "Rencana Tata Ruang Wilayah", at Province and also Sub-Province. It plan had been including of area protected which must be paid attention. According to this research, the area function can be determined pursuant to SIG model and obtained by area protected for the width of 644.036,13 Ha and also for conducting area the width of 558.438,45 Ha. 62,38 percent of area protected still closed over by forest area consisting of primary forest area for 347.612,32 Ha equal to 54,02 percent and also secunder forest for the width of 53.771,14 Ha. The area protected is usually specified to become area protected by government in Regonal Planologi Plan of North Sumatra ("called RTRWP"). But not all of become area protected goodness in the form of natural protected forest. From data processing with Geographical information System (CIS), there are of 315.715,40 Ha which ought to become area protected not be specified by Regonal Planology Plan of North Sumatra. Pursuant to the fact writer suggest to Region Government of South Tapanuli and Region Government of North Sumatra for return protected forest function especially area which still have forest as a land cover and also a land farm which not forest but entering into protected forest category pursuant to Surat Keputusan Menteri Pertanian No.837/Kpts/Um/l 1/1980. Besides require to be performed by review to Regional Plan Planology of North Sumatra Province specially for the region of South Tapanuli. 001201033